Sign support bracket



FIG. 1 is a right front perspective view of a sign support bracket, showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a side elevational view thereof;

FIG. 5 is a rear elevational view thereof. 

The ornamental design for a sign support bracket, as shown and described. 